Poppet valves are well known in the art and include a piston mounted for reciprocation within a cylinder. The piston includes a disk-like head attached to a stem, and the internal wall of the cylinder has a seat formed therein to define a flow orifice between the cylinder seat and the piston head. Typically, the piston is driven by a cam or by suitable pneumatic or hydraulic means. In operation, the fluid flows into the cylinder under pressure and causes the piston to reciprocate so that the piston head moves away from the cylinder seat, creating a flow orifice therebetween. The maximum pressure is obtained when the piston head moves away from the cylinder seat to define the largest flow orifice. After this occurs the downstream flow pressure decays to zero. The total time span for the cycle to occur only takes a few seconds, which time is critical in certain applications. For example, in aircraft, the poppet valves may be employed to control the opening of emergency exits so that the fastest possible operation is critical. In conventional poppet valves, the time required to discharge a 500 cubic inch cylinder charged to 3,000 PSIG is in the range of 4 to 5 seconds. Accordingly, as the discharge time is critical, it would be highly desirable to design a poppet valve which minimizes the operating time of the valve to reach maximum pressure and to discharge the cylinder.
Broadly, it is an object of the present invention to provide an improved poppet valve which overcomes the aforesaid problems. Specifically, it is within the contemplation of the present invention to provide an improved poppet valve which is constructed to significantly decrease the operating time of the valve to discharge the cylinder by specifically defining the shape of the working surface of the piston head which is adapted to engage the cylinder seat.